4. [20 points] Environment Recycling, Inc. must clean up a large automobile tire dump under a state environmental cleanup contract. Some of the activities can be crashed. The tasks, durations (in days), costs, predecessor relationships, the crash times, and costs associated with performing the activities at their original (normal) times and for the crash times are shown as follows: Activity Immediate Predecessor A B none none B D E F G H Normal Time (days) 3 5 4 5 6 4 6 Normal Cost ($ 000) 3300 4100 3700 5900 6700 4100 9100 2700 Crash Time (days) 2 3 3 4 4 3 3 4 Crash Cost ($ '000) 3800 4500 3800 6000 7500 4150 9700 3000 DE E,G olm uno MGMT 3106: Management Science and Operations Management a. The critical path for the project is A-C-E-G-H. Find the normal total project completion time and normal project completion cost. Show calculations. b. What activity should be crashed first in order to accelerate the project? Why? . The project needs to be completed three days early. Which activities need to be crashed? In which order? Explain why you selected those activities. Show calculations. d. What is the project cost to finish three days early? Show calculations